I was lucky enough to see a magnolia like that in a local park last week, not sure if it was the same variety as yours but the flowers were fragrant when I smelt them up close. Wonderful flowers on your tree may I say, I am sure the bees will be visiting the stamens inside the magnolia flowers too and also may I say that as well as the genista you mentioned, the bluish purple vinca flowers in the hedge behind the magnolia go really well too in terms of colour!
